Rheological instrument



March 10, 1953 J. E. TYLER RHEOLOGICAL INSTRUMENT 2 SHEETS-SHEET 1 FiiedSept. 14, 1950 IN V EN TOR.

2 SHEETS-SHEET 2 INVENTOR.

JOHN E- TYLER.

. J. E. TYLER RHEOLOGICAL INSTRUMENT 4 6 M Q r v m M ==II-r-5 n w A.ilrlflmlw wall/I m0 i55 e M I N ii: 2 w x Y m HEN EC 7 l v 2 m"l'lv'l'hl'h C 3 a 1 2 w 6 5 6 6 6 March 10, 1953 Filed Sept. 14, 1950Patented Mar. 10, 1953 "RHEOLOGICAL INSTRUMENT JJohn:ELTylenRiverside,Conn., assignonto-Interchemical Corporation, New york, N..Y.,.a,.cor-

v 11 ration-0f Ohio r lpplicationseptember 14, 1950Serial No; 184,881

lhis inventionrelates to an instrument and to-methods formeas-uringrheological; properties of' liquids.

Ibis an object of the invention to provide-an imprcvedinstrument and newand improved methods for such rheologicalmeasurements.

"It is a more specificobject'tcprovide a simple rheological measuringdevice which is characterized by high sensitivity over an inherently*w-ide measuringrange.

It is a still further object to provide improved means and methods forcontinuous rheological measurementsoftest fl-uids which are subject tovariations in their -"rheological properties, by comparing them withstandard-fluids the rheologicalproperties of l which are known.

Othercbjec-ts of *theinvention will be apparent "from the descriptionand the accompanying -drawing;- wherein- Figure 1-is *a perspective viewof anembodi- -ment of the invention,

Figure 2 is-a-vertica1,-part1ysectional eleva- =tion.

Referring in moredetail to-the drawings, there its-shown a baselflhaving-a bracket 1 I attached to it. =-I-Ie1dbetween the overhangingpart 12 i of the-bracket and --the-base is a frame l3 which is-rotatablymounted, asshown in Figure 2, by means of the pins 1 4.1 and l5 fitting into ball bearings of which the ballbearing [6 isinserted intothe base and the ball bearing I1 is set inthe "aforementionedover-hangingpart of the bracket. *At -1east one of the ball bearingsismade adjustable, as-shown," by means of-'a set screw I8.

Mounted-within l the frame which, for-example, is 5% -inch. high,= 1%inch.-wide-and 1% inch. deep,- 'isa--sma11,"--60 cycle-110 voltsynchronous -'-motor--2p,"operating-at, say, 600 R. -P."-M. By

meansof screwspsuch as shown at 2 I, the base of the moter--isfastened-to one of i the sidewalls of the frame which has a boring l9of-sufficiently large diameterto provide clearance for'the motor shaft22, havingadiameter: of, sayg inch: and

extending -from the 1 base a of the "motor through theirame. Attached tothe shaft is a pinion23 which,according. to this embo'diment, has 12teeth at-a pitch of 32.

A-' shaft 24, having a diameter of, say; inch and-a length of '13 inch.,is held by the ball bear- '-i ngs 25 and-26 inserted into boringsprovided in the-frame. Preferably, the axis of-rotation of the frame;the-shaft 22-extending from the motor and the shaft =-24 lie in the samevertical; plane. The distance from oneshaft' to the other-is such "that?a spur -wheel 21; attached to shaft; 24 and having; say, 1 12 :teeth.iat a;; tch-..;0 .321: mesh i with the foregoing pinion.

:"Disks, such as thedisks 30.;and 3I-..area provided "to be attached tothe: armsof the-shaft .z lextend- .ingrfromthe frame 13.iAfirst-setoftwo disks has a:diam'eter of,-say,- 4 inch. and; athickness "of he inch. Eor oner;speci ficpurposeof the in- .vention,additional. disks. are provided, which are interchangeable with,the--disks of the ,first :set.

the frame.

As shown; the disks; are --ins erted intotanks liil and. 4 I, one ofwhich isintended; as; areceptacle -for a standard -;1. qu nd the Qthen-acepxtacle for -arstm ple liquid. For one particular use of the device,.the receptacle for .the ,sample .xliquid -is to be. .iurnished -inthe;- known; manner, (With an; inlet; preferably at the bottom a bafiieplate underneath thefliskto distribute the:- intcomine liquid eveniysihexrecep mt-an .cverfiow p pei o. k e t e-l q dat a n t nt ve which;incidentallyr; mnstbe. exacflyathawme-i both.tanksduri g: he es n;Current is..suppliedwto':the;motonbycmeansiof two wires. The .wire.; 5l.leads sfromaarhowfir --source; to x-the-gball bearing :1 :andefrcm'th:through thewpini M and :the; frame I 3 tonne-ite --mina1 of .the motor,.while the Wire-25120111166178 --the other terminal, to the pin .15.:and .ttheiball .bearing l1, and ,:thence connects toggthe mow-er.source. .As;indicatedtbygthernumerals 53,154 and .=55,:1the ibearings.are insulatedagainst the base 10,..the overhanging part-112;.of..the..bracket, and theframe 1.3,.respectively.

The' instrumentis;fittedawitmat least one heliacalspring to. counteracttorsional.forceseexerted upon "theaxisot rotationof shaft 24 andframel3. -WhileIfind'it'convenient to :connectza single helicalspringhetween.itheltop of frame |l3=and the overhangingpart l2 of thebracket, another identical .spring .can be connected :between-:thebottom'ofthe frame l3. and thebase 12. Accord- .ing tothepresent.embodiment the spring fil. is .fastened at one, end..to thec1am 162: andat the other end to the sleeve 63which-ismounted-underneath thecverhanging. part 12 of the bracket so asto encompass the pin l5. Attached to one side of this sleeve is a lever64 which is held being wedged between the overhanging part l2 of thebracket and a plate 65 attached underneath to the said part. The leveris held rigidly, but nevertheless, rotatably if some force is exerted.Upon turning, the tension of the spring is increased or decreased,depending upon the direction in which the lever is moved. The purpose ofthe lever is to set the instrument at zero, as determined by the pointer66, mounted in cooperative alignment with an empirical scale 61 on topof the overhanging part [2 of the bracket.

The instrument must be properly balanced. For this purpose, a mass 36,equal to the mass of the motor 20, is fastened to the frame l3 oppo-.

site to the motor, while the mass of the pinion 23 and the spur wheel 21is balanced by the pointer 66.

For comparing the consistency or viscosity of two fluids, thereceptacles are filled each with one of the two fluids, preferably to aheight well below the shaft of the disks when the latter are inserted inthe receptacles. As long as two disks of equal dimensions and equaldistance from the axis of rotation of the frame are turned at the samespeed While partly immersed in the same fluid medium, no movement aboutthe axis of rotation of the frame will occur. But if the disks arepartly and equally immersed in fluids which differ in viscosity orconsistency, the assembly will turn about the axis of rotation of theframe whereby the resistance of the restoring force provided by thehelical spring will be partly overcome until an equilibrium is reachedbetween these two forces. Since the amount of torsional force isproportional to the difference in viscosity or consistency of the twofluids, the scale can be calibrated directly in units of viscosity orconsistency. If, in comparing a very viscous liquid with a standardhaving a much lower viscosity, the distance between the axis of rotationof the frame and the disk immersed in the very viscous liquid must before-shortened as against the distance between the axis of rotation ofthe frame and the other disk in order to obtain a balance point withinthe operative range of the helical spring, the viscosity or consistencyof the sample liquid can be determined by applying a factor to the scalereading. It is the purpose of the markings 34 on the shaft 24 toindicate fore-shortened distances providing factors which are simplemultiples of the scale reading.

Scale readings obtained with one set of identical disks immersed in twodifferent fluids are characteristic of the differences in internalproperties of the two fluids. By filling the two receptacles with thesame fluid and replacing one of the two identical disks by another diskhaving the same diameter but different thickness, or having the samethickness but a different diameter, or differing in diameter andthickness from the remaining disk, and operating the instrument, the

resultant scale reading is influenced, in part, by

4 characteristics of fluids and furnishes data relating to surface dragand, indirectly, to surface tension of fluids.

For example, the two receptacles are filled to equal levels with theliquid to be tested. Identical disks are mounted on the shaft at equaldistances from the center and, while the instrument is operated, thepointer is adjusted to read zero. One of the disks is then replaced byanother, having the same diameter but greater thickness, and the fluidlevel of the receptacle receiving this disk is adjusted to be equal tothat of the other receptacle. The torque at the substituted disk,resulting from the operation of the instrument, now differs from thetorque at the original disk, because (a) there is a change in theaverage velocity of the rotating disk, (b) there is a change in theimmersed surface area of the disk and (0) there is a change in theeffect of surface characteristics of the fluid because of the change inthe length of line of contact between the disk and the fluid surface.Since the values of (a) and (b) can be determined from the experimentalconditions, they can be applied to correct the scale reading. Bcalibrating the scale of the instrument in force units and dividing thecorrected reading by the diiference in the length of the lines ofcontact between the fluid surface and the two disks, surfacecharacteristics per unit length are obtained.

I claim:

1. An instrument for testing rheological properties of fluids,comprising two receptacles for holding samples of fluid, two disks ofequal dimensions fastened to a common connecting shaft arranged topartly'immerse one of the said disks in the fluid in one receptacle andto partly immerse the other of the said disks in the fluid in the otherreceptacle, a support for the said common shaft rotatably fitted ,topermit the said shaft to turn freely about its center in the horizontalplane, means mounted on the said support for rotating the saidconnecting shaft about its axis, means for opposing torsional forcesturning the said shaft about its center in the horizontal plane and forrestoring the said shaft to an initial position upon removal of suchtorsional forces, and means indicating the degree of angulardisplacement of the shaft from the initial position.

2. An instrument according to claim 1, provided with markings on thesaid common con necting shaft to readily attach the said two disks tothe shaft each at an equal distance from the center of rotation in thehorizontal plane of the said shaft and to foreshorten the distancebetween one of the disks and the said center of rotation to apredetermined fraction of the distance between the other disk and thesaid center of rotation. I

3. An instrument for testing rheological prop erties of fluids,comprising two receptacles for holding samples of fluid, two disks ofequal diameter but unequal thickness fastened to a common connectingshaft arranged to partly immerse one of the said disks in the fluid inone receptacle and to partly immerse the other of the said disks in thefluid in the other receptacle, a support for the said common shaftrotatably fitted to permit the said shaft to turn freely about itscenter in the horizontal plane, means mounted on the said support forrotating the said connecting shaft about its axis, means for opposingtorsional forces turning the said shaft about its center in thehorizontal plane and for restoring the said shaft to an initial positionupon removal of such torsional forces, and means indicating the degreeof angular displacement of the shaft from the initial position.

4. An instrument for testing rheological properties of fluids,comprising two receptacles for holding samples of fluid, two disks ofequal thickness but unequal diameter fastened to a common connectingshaft arranged to partly immerse one of the said disks in the fluid inone receptacle and to partly immerse the other of the said disks in thefluid in the other receptacle, a support for the said common shaftrotatably fitted to permit the said shaft to turn freely about itscenter in the horizontal plane, means mounted on the said support forrotating the said connecting shaft about its axis, means for opposingtorsional forces 6 turning the said shaft about its center in thehorizontal plane and for restoring the said shaft to an initial positionupon removal of such torsional forces, and means indicating the degreeof angular displacement of the shaft from the initial position.

JOHN E. TYLER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,664,752 Konig Apr. 3, 19282,092,640 Dallman Sept. 7, 1937 2,280,947 Gulliksen Apr. 28, 1942

